Brake



Feb. 10, 1931. R. F. KoHR 1,792,225

BRAKE Filed April 4. 1928 2 Sheets-Sheet l IN VEN TOR.

"ATTO Y Feb 10, 1931. R. F. Kol-1R 1,792,225

BRAKE' Filed April 4, 1928 2 sheets-sheet 2 IN VEN TOR.`

I BY

- ATTO EY Patented Feb. 10,1931

UNITED STATSLPAT ENTl ori-fics vROEEEJI E. Kona, orvsonrn BEND, namens, Assrenoa 'ro rrHE s'mIDEBAKErt conIV` Y roVEATYIoN, or soUTH BEND, rnnrnnn, E coEroEArIoN or NEW JERSEY BRAKE Application fue-1 .apra 4,1928. serial No. 267,427.

particularly tothe operating'means therefor, the'principal object being to provide a vehicle brake of the internal-'expanding type which, compensates`for uneven wear of the brake elementf Y Another object is to'provide aivehicle brake..

of the internal-expanding type Vwith -means which permits free expanding action of the f cam support.

operating cam. v I

Another object is to provide a vehicle brake of the internal-expanding type ,withzan operatingca-m which is free .to move with the brake element as well as to rotate during expansion of the brake element. y y YA further object is to provide aV vehicle brake ofthe internal-expanding type with a rotatable brake campositioned betweenthe ends of the brake element, and a resilient arm which rotatably supports the brake cam shaft whereby the cam is free to move to compensate for wear of the ends of the brake element and which is free to return to its normal iposition independently of the brake element.`

rlhese beiner among the objects of the present invention, the same consists of certain featuresv of construction and combinations ofl parts to be hereinafter described with refer .ence tothe accompanying drawings, and then claimed, having the above and other objects Y in view.

In the accompanying drawings which illus. trate a suitable embodiment of the present one end pivotally anchored on a pln 25 sethe line 2-2 of Figure 1 showing the cam supportin detail. n Y

Figure 3 is an enlarged'section taken on the line 3 3 of Figure 1.

Figure 4 is a partial rear elevation of the brake looking toward the rear side ofthe backing plate to show the opening therein which permits movement of the brake cam .and shaft. Y

`chored by an articulating Y the'free end of the. secondary shoe 17; and aV vreverse shoe 23 having its arcuate face cov- Figure 5 Vis anienlargedkperspective view `of the cam shaft support.'

Figure 7 is a section taken on the line 7,-7 Y of Figure 1.

Figure 6 is a perspective View of the resilient spring member for the Vcam support.V i-with operating-meansffor the brake element Y Figure 8 is a section taken on thelin-e k8-#8V of Figure 1.

Figure 9 is a fragmentary front velevation of a Lbrake showing a modified form of brake Figure 1G is an enlarged perspectiveview of the modied form of brake cam support shown in FigureQ. ,Y Referring to the accompanying drawings in which like numerals refer to, hke parts throughout the several views, the brake shown forillustration in which thevpres'ent invention isembodied comprises a brake drum 15V adjacent to which is a dust cover or backing plate 16. l/Vithin the drum l5 is the friction element comprising a secondaryshoe 17 havingits arcuate face, covered with friction material 20 as shown in Figure land having one end thereof pivotally anchored toa pin 18 secured to the backin'gplate'l; a primary shoe 19. having its arcuate facey covered with friction material 21 and having a bifurcated V7o y end which telescopes the free end of the sec-`Y ondary shoe 17 and which is Vpivotally anered with friction material-`241and having cured to the backing plate 16.

As shown in Figures'l, 7 land 8, the.v anchored ends'of the secondary and reverse shoes 17 and 28 respectively overlap each other, the secondary shoe 17 being provided with an enlarged opening 26 intermediate itsM ends through which the anchorppin 25.f0r

movement of the shoel 17 about the pivot pin V1S. The reverse shoe 23is likewise provided so pm 22 carried by the .reverse shoe 2,3 extends .to allow-pivotal' end to a pin 29 secured to the backing plate 16 and whichis attached at its other end to the free end of the secondary shoe 17 normally holdsthe shoe out of engagement with the brake dru1n"15. A second lcoi-l spring 3() attached atits endsto the free ends ofthe primary and reverse shoes 19 and ,23. nor mally .holds these shoes out of engagement withlthe brake drum and draws them', in-

wardly toward each other so 'that'their ver-A tical Contact faces 31 engage the sides of the operating` cam 32 which is about to be described.

The cam 32 is either formed on the end of or is 'securedV ito Ythe fendv f of a `rotatable shaft 33 which is rotated by a lever 34 suitably connectedy to .a brake pedal or handlever .(not

shown'i.- When the cain32 is rotated bythe shaft 33, its ends bear against thev contact plates 31`of the brake shoes 19 and 23110 move Y the same into engagement with the brake drum to thereby retard the rotation of theV same. i

In conventional constructions the cam shaft 33 is journaled in a lined bushing and is only 'free to rotate and no provision is made for uneven wear vof the friction facing of the brake shoes. For example, after con- :siderable use, the friction facing 24 of. the

reverse shoe 23 `is worn more than the friction facing 21 4of the' primary shoe 19 andffull benefitfof the reverse shoe 23 is not obtained.

Vhensthe cam 32 is rotated it causes the-shoe. z. f 19 toengage thedrum 15 before the shoe 23 because the facing 2e of the shoe 23 -is worn` to a greater extent than the fac-ino' 19. This, coupled up with the factvthat t e primary shoe 19 is not very effective'when the -druin 15 is @rotatingin -a reverse direction, vmakes avery inefficient brake especially when no benefit is derived from the reverse slice 23. This is also true whenvthe yfacing 2-1 of the primary shoe 19 vhas worn more than that of the reverse shoe 'ln this case, the full benefit of the primaryshoe 19 is not obtained because lthe construction ofthe 'cam 32 necessarily causesthereverse shoe 23 to be engaged with the brake drum 15 before the shoe 19.

It is apparent'thatfa more elhcient and more effective brake will be obtained when some means is provided tocompensate for wear-of the friction facing of the brake elements which allows proportional application -of braking pressure, and this invention seeks to accomplish thisdesired result and overcome theobjections just mentioned. The shaft 33 for the cam 32 is preferably journaled in a bracket35 which has a flange 36 slidabl'y seat- -ed against the inner face of the backing plate 16, opposed ribs `Orbeing formedv integral with Vtheflange 36 to serve as guides for and againstwhich the free ends of the primary and' reverse shoe slidably rest, and a cylindrical portion 37 extending outwardly through .ofthe .ribs of the bracket 35, a'vertical resilient portion and a horizontal lportion e3,i the end ofwhich is rolled to receive y'boltflilt i which securesthe saine to the backing plate 16. Y c i 1n order to illustratethe operation of the bra-ke-cam'support, the friction facing 24 of the reverse shoe 23 will be considered as bev ing wornunore .thanand-:consequently of iless thickness thanV ,the 'facing 2.1Y 'ofthe shoe 19 andthel drum lwillibe ,consideredV as rotatf ing 1n a-'clockwiseidirection as viewedin Fig ure Lowhich `in-xiea'lity-is the direction in,-

which the same rotates when ythe motor vehicle is being backed up. V'When the brakes. 7

are applied `in thisicasefthecam [32 isrlotated ina counterclock-wise-direction bythe lever 34and shaft 33l whichfcauses :the lbrake shoes 19 and 23 to move outwardly. A The shoe 19 engages-:theA-drum 15. before theshoe 23 ibecauseof the differencesin thickness ofthe friction facings, -and ybecause-the drum v15-:isigo-A tating in -a clockwise direction against the movement of the shoe 19 very little effective braking is obtained.

Thisis overcome liowe-ver, by-tlie fact thatY the stalnpings 39 whichsupp ort-:the `cam shaft journal 35, are of spring-metal'. and fleX a sufficient amount toallowthecam l32'Yto swingt-othe right in order to move the shoe 23 inengagement with the brake drum 15 so that full` braking action and full ybenelitof the reverse shoez23 is obtained. The opening 38 inA the backingfplate 16 through which the cam shaft journal 36 :extends is of sufticientxlength to allow theswinging-movement-of the cam 32 whereby braking .pressurel is `equalized ybetween 'the two shoes and wearing of the ends of the friction facings Vis compensated for. When the braking pressure is released the resilient stampings 39 swingvther'cam 32 vback pto-the ilionmal-positionfshown invFiigure 1 so.

that when in this normal position the brake shoes ,are .correctly spacedfrom Athe drum 15 andare held out of engagement therewith by the coilsprings 28..and`30.v

A modification of the cam support is shown in Figures 1() and'l'l. 'The support shown in these figures is forged froinasingle 4pieceof metal to va V"lshape and comprisesa vhorizontal portion 50 which is secured' at its endby bolts '51to the backing platelii, lan integral vertical riser 52 of thin-cross Vsection pref'- erably rtempered toinake the same resilient, and a circu'lar'journal 53 formed integral withthe upper end-of thejrise-r `52havinglout y wardly projecting ribs .tzanel sacentral opening 55 which receives the shaft 33 offth'ecam pivoted shoe brake, and

from the spirit and invention, the scope `to this time. None of the previous constructions have been provided with a support for thebrake cam shoe Awhich is swingable to compensate for wearing of the ends of the rake shoes and which is of such a resilient nature that after braking pressure is released, it will return to its normal positionindependently of the braking element.

Although the present invention is embodied in a three-shoe brake, it is to be un-` derstood thatrno -claim is made to the construction of the brake proper other than the operating means therefor. It is also to be understood that this invention is easily adaptable for use with a band brake as well as a A that formal changes may bemade in the specific embodiment of the invention described without departing substance of the broad of which is commensurate with the appended claims.

` l/Jhat I claim is:

l. In a brake mechanism, a rotatable drum, a backing plate adjacent thereto, a brake element engageable with said drum, a rotatable cam between the ends of said brake element for moving the same into engagement with said drum, and a resilientA member iiXedly mounted on said backing plate supporting said cam to permit the same during rotation thereof to move with an end of said brake element.

2. In a brake mechanism, a rotatable drum, a brake element engageable therewith, a rotatable cam positioned between the ends of said brake element for moving the same into engagement lwith said drum, a shaft for rotating' said cam, a support for said shaft comprising a journal tion secured to said backing plate for allowing said cam during rotation thereof to move with an end of said brake element.

3. In a brake mechanism, the combination with a rotatable drum, a backing plate adjacent thereto, and braking means engageable with said drum, of a rotatable cam for moving said braking means into engagement with said drum, means for rotating said cam, and resilient means iXedly mounted on said backing plate for supporting said last mentioned means to allow said cam during rotation thereof to move with said braking means, said resilient supporting means being adapted to return said cam to normal position independently of said braking means.

4. In a brake mechanism, the combination with a rotatable drum and a brake element .vertical portion portion and a resilient porengageable therewith, of a rotatable cam engaging the free ends of sald brake element for movingthe same into engagement with said drum, a 'shaft for rotating said cam, a supporting journal for said shaft, and a resilient member fixed at one end and secured at its other end to said journal for allowing said cam to move during rotation thereof with an end of said brake element, said resilient member being adaptedv to return said cam to norf mal position independently of said brake element. Y

[5. In a brake mechanism, the combination with a rotatable drum and a brake element engageable therewith, of a backingplate adjacent to the open endv of said drum having a slot therein, a rotatable cam positioned be-V tween the free endsof said brake element for moving the'same into engagement with said drum, a shaft extending through said slot in said backing plate for rotating said cam, a

journal"surrounding said shaft, anda resil-' ,v ient arm supporting said journal having its Y free end rigidly secured to said backing plate,

said support permitting said cam during rotation thereof to move with an end of said brake element for insuring engagement of said end with said brake drum.

6. In a brake mechanism, the combination with a rotatable drum and a brake element engageable therewith, of a backing plate adjacent to the open endvof said drum having a slot therein, a rotatable caml for moving said brake element into engagement with said drum, a shaft extending through said slot in said backing plate for rotating saidl cam," a journal for said shaft, and a resilient T- shaped support the horizontal portion thereof being secured to said backing plate and the free end of the thereof being secured'to said journal for allowing swinging movement of Ysaid cam to compensate for wear of said brake element. A Y

7. In a brake mechanism, the combination witha rotatable drumand a brake element for said journal, the ends of` f engageable therewith, of a rotatable cam positioned between the free'ends of said brake' element for moving the same into engagement with said drum, a shaft for rotating said brake element, a journal for said shaft, and an inverted Tfshaped support for said shaft comprising a pair of resilient oppositely disposed stampings secured together having the free ends of the vertical portions thereof secured to said journal, the vertical portions of said support being flexed during rotation of said cam to allow said cam to move with an end of said brake element to compensate for wear of the same.

Signed by me at South Bend, Indiana this 28th day of March 1928. V i

ROBERT F, KOI-IR. 

